Computer Tomography (CT) uses computer-controlled X-rays to scan human in stratum. It can accurately display an anatomical structure by comparing the different densities of human body tissues presented under X-rays. Medical images obtained by CT are usually inspected and measured by physicians or the like to obtain required characteristic data as diagnostic basis. However, the measuring method for diagnostic reference values of CT images in the prior art depends more on manual work, resulting in a low efficiency and an insufficient precision.
For example, Chinese patent application No. 03136006.8 discloses a medical image processing apparatus for processing medical image(s) generated by a medical image device, and the medical image processing apparatus includes: an interface, configured to obtain medical image(s); a processor, configured to determine a smooth line along an arched portion of a sample in the medical image(s) obtained by the interface; and a computing apparatus, configured to compute the camber of the arched portion based on the smooth line determined by the processor. Some characteristic data, such as the camber of the arched portion, can be obtained by use of the above image measuring method.
However, to obtain some preciser and complexer characteristic data, it is needed to collect the basic characteristic data such as CT value and volume precisely and quickly and to have a large amount of complex computation. At this point, the existing measuring method becomes insufficient.
For example, for determining the characteristic data of a part with a complicated shape, such as the accurate volume of the part, the following measuring method is usually employed in the prior art: a few scattered edge points in the critical area of the part under test are collected to determine an approximate contour, and then the volume of the part under test is determined based on the empirical volume value of the part. This method often creates a big error. In another method, a region is approximately determined by an operator according to the obtained images, for example, the region is marked on each single-slice CT image by a curve, then the region is measured in various ways, thus the volume of the part under test is obtained. Although the volume of the part under test can be obtained by the above methods, due to the complex shape of the part under test on the medical image, it is difficult to obtain an accurate value and sufficient parameters. As a result, the characteristic data obtained such as volume have a low precision and cannot be applied to cases with high precision requirement. Moreover, because the above methods depend more on personal experience and manual operations, the efficiency is usually very low.
As another example, it is required to obtain the average value of a certain characteristic data of a part under test. The following method is usually employed in the prior art: the part under test is scaned by CT to obtain tomographic images of an appropriate position thereof; some discrete points at the position of the part under test on the images are selected, and the average value of the characteristic data of these discrete points is computed so as to approximately obtain the average value of the certain characteristic data of the part under test. However, due to the fact that the distribution of the characteristic data in the part under test is not always uniform, the precision of the average value of the characteristic data obtained by the above method is usually low. In order to improve the precision, the operator need to determine and collect lots of representative points to obtain a more accurate result, at the cost of much more time and cost and a lower efficiency.
Consequently, by use of the prior art image measuring methods, the resulting precision of the characteristic data of the part under test is relatively insufficient, or the speed and efficiency of the measuring process are very low (that is, considerable time and cost must be taken to improve the precision).